The present invention relates to a disazo compound and a process for dyeing a substrate therewith.
Although a large number of dyes are used for dyeing and printing of various fiber materials, leather, paper or pulp, few of them show satisfactory dyeing characteristics such as dyeing velocity and degree of exhaustion.
In particular, since the existing black dyes used for black dyeing of paper and pulp exhibit low dyeing velocity and degree of exhaustion, it is a problem that the deep black dyeings can be obtained only with difficulty, and also the water-fastness of the dyeings is unsatisfactory.
A rationalization of the processes used in the dyeing industry is more and more required, and from the point of view of reduction of dyeing time and environmental conservation in particular, the demand has arisen to develop such dyes of high dyeing velocity and degree of exhaustion as to give nearly colourless waste water from dyeing, and also exhibit excellent water-fastness of the dyeings. The amount of black dye to be used to obtain black dyeings runs to several times as much as compared to the dye of the other shades, so that the development of dyes which exhibit an excellent dyeing velocity and degree of exhaustion and also produce black dyeings of an excellent water-fastness is very urgently in demand.
The inventors of the present invention have intensively investigated to discover a black dye which yields excellent colour value (depth of shade), exhibits high dyeing velocity and degree of exhaustion, and possesses excellent water-fastness, or conducting dyeing and printing of various substrates, for example, fibre material, leather, wood, pulp and paper, and so have attained the present invention.